You're going to need the dimensions of your board. So assemble all your pedals in the way in which you would like them to look on a board, then sqaure it off with electric tape. You can measure the lenght of the tape, and you'll have your base dimensions. From here.. you can go just about anywere, you can make it a flat board, you can make it in step form, or slanted. It's all a matter of preference, there's no set material for what the board is made of, but you will want something durable.

If you made it in a two step tier, you could probaly store the power supply and most of the cords under the step, so they'll be concealed from view and won't get in the way.

The more creativity the better, you should sketch a few designs first, that way you can be sure of what design you like, then go about building it.

Pedal boards range from a piece of wood with some velcro on it, to a diamond plated piece of steel with the stompboxes screwed into it.

You could also make a pedalboard within a carrying case, that way you can cart it around fairly quickly. Or you can just make a covering for it..